1. Field of the Invention
The field of this invention relates to earthquake safety technology, and more specifically to actuating mechanisms for actuating a valve or an electric switch in response to seismic activity.
2. State of the Prior Art
Seismic safety valves are known. The present inventor is also the inventor of the following patents and applications related to seismic safety technology, all of which are incorporated herein by reference:
U.S. Pat. No. 4,903,720;
U.S. Pat. No. 5,992,439;
U.S. Pat. No. 6,085,772;
U.S. Pat. No. 6,705,340;
U.S. Pat. No. 6,938,637;
U.S. Pat. No. 7,458,387;
U.S. Pat. No. 7,814,924; and
U.S. Patent Publication No. 2009/0065068.
Each of U.S. Pat. Nos. 4,911,029, 4,161,183, 4,821,759 and 4,429,704 includes the concept of a quarter turn valve that is turned by a spring loaded actuator to shut off the flow of, for example, gas, in response to an emergency condition such as a seismic event. Each includes some form of sensor to release the spring to cause the valve to turn.
In particular, U.S. Pat. No. 4,429,704 has a housing with a built in rotor with a spring loaded to turn one quarter turn to shut off the valve upon the occurrence of a seismic event. A latch element maintains the rotor in place until the seismic event happens. The sensor is a pendulum device that allows the latch to move under force of the spring.
U.S. Pat. No. 4,911,029 uses a ball and pedestal as a sensor to mechanically release a spring loaded actuator. The springs drive a rack which turns a pinion which turns a valve. This arrangement is quite complicated, and involves a clutch mechanism for the purpose of resetting the device.
U.S. Pat. No. 4,161,183 uses a ball and a spring loaded cylinder to turn the valve stem and has a complicated release mechanism. An arm 54 pivots about point 57 when the ball moves arm 75 to release arm 54 and thus arm 28. Arm 28 is connected to a spring loaded cylinder.
U.S. Pat. No. 4,821,759 has a spring loaded valve. A handle or bar 14 is prevented from releasing by a detent ball member 82. This is released upon a seismic event through a sensor mechanism.
U.S. Pat. No. 4,546,660 addresses the concept of actuating a standard valve.